| Bay Flooring LLC | Espinoza Adrian Fragoso | — | (925) 521 4656 | Other | Concord · Contra Costa County | — | — |
| Bay Flow Sewers | William Osvaldo Veliz Mejia | — | (510) 630 5116 | Other | San Pablo · Contra Costa County | — | — |
| Bay Garage INC DBA Bay Garage Closet Systems | Oran Cohen | — | (925) 885 8586 | Other | Concord · Contra Costa County | — | — |
| Bay Geometree | Bay Geometree | baygeometree@gmail.com | (510) 590 0893 | Other | Richmond · Contra Costa County | — | — |
| Bay Green Landscape INC | Delmar Jose De Oliveira | bglandscapeinc@gmail.com | (650) 996 0076 | Windows, patio, painters | Rodeo · Contra Costa County | — | — |
| Bay Harbor Remodeling And Construction | Jose Luis Perez | — | (786) 753 4013 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Bay Hawk INC | Mary Beth Wika | — | (510) 223 3142 | Other | Pinole · Contra Costa County | — | — |
| Bay Home Remodeling INC | Gal Igal Nunu | — | (415) 583 5060 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| Bay House Flooring | Bay House Flooring | — | (925) 330 8697 | Other | Walnut Creek · Contra Costa County | — | — |
| Bay Insight Builders LLC | Hugh Vanho | — | (510) 203 7881 | GC, remodel, ADU | El Cerrito · Contra Costa County | — | — |
| Bay Modern Build INC | Zhenying Jiang | — | (510) 375 6298 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Bay Pacific Concrete | Bay Pacific Concrete | — | (510) 901 9689 | Other | San Pablo · Contra Costa County | — | — |
| Bay Plumbing & Rooter LLC | Leopoldo| Leo Gonzalez | — | (510) 948 8442 | Other | Rodeo · Contra Costa County | — | — |
| Bay Pros Construction INC | Mario Antonio Funes Bolanos | — | (650) 218 3042 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Bay Radio And Alarm | Bay Radio And Alarm | — | (925) 322-8995 | Alarm and generators | Walnut Creek · Contra Costa County | — | — |
| Bay Side Fencing | Bay Side Fencing | — | (925) 420 6268 | Other | Antioch · Contra Costa County | — | — |
| Bay Structural Iron Works INC | Damian Armando Esparza | — | (925) 219 5583 | Other | Antioch · Contra Costa County | — | — |
| Bay Valley Roofing | Raul Diaz | info@bayvalleycontractors.com | (925) 705 7889 | Other roofers | Concord · Contra Costa County | — | — |
| Bay Valley Roofing & Solar | Bay Valley Roofing & Solar | info@bayvalleycontractors.com | (925) 428-6614 | Other roofers | Pacheco · Contra Costa County | — | — |
| Bay View Building And Remodeling | Francisco Javier Bravo | — | (707) 450 6275 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Bay Vista Construction INC | Wilber Antonio Chicas Galicia | — | (650) 839 7928 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Bay Wide Glass INC | Jill Marie Freitas | — | (925) 960 8780 | Windows, patio, painters | San Ramon · Contra Costa County | — | — |
| Bay-valley Painting INC | Jared Louis Cuevas | — | (925) 766 9912 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| Baygreen Landscaping INC | Raul Longoria | — | (925) 334 9020 | Windows, patio, painters | Pittsburg · Contra Costa County | — | — |
| Bayland Welding Fabrication | Bayland Welding Fabrication | — | (510) 685 8476 | Other | Richmond · Contra Costa County | — | — |
| Bayridge Construction | Peter Richard Sadler | — | (650) 400 1593 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Bayshore Construction Co | Tony D'andrew Castaneda | — | (510) 830 5616 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| Bayside Contractors | Luiz Martins Avila | — | (866) 287 2837 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Bayside Insulation & Construction INC | Shahram Mohammad Jaf Ameli | — | (925) 288 8960 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Bayside Trenchless INC | Guzman Guadalupe | info@baysidetrenchless.com | (510) 806 5033 | Other | Antioch · Contra Costa County | — | — |
| Baysites Electric | Garcia Homero Suarez | baysiteselectric@gmail.com | (707) 298 4784 | Electricians | Concord · Contra Costa County | — | — |
| Bayview Home Inspections | Bayview Home Inspections | — | (510) 435 8390 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Bayview Landscape And Maintenance LLC | Peter Albert Harthun | — | (424) 303 1877 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Bayview Painting Co INC | Peter Andrew Dewey | — | (925) 440 7985 | Windows, patio, painters | Moraga · Contra Costa County | — | — |
| Baywood Construction | Jose Guadalupe Gutierrez Mendez | — | (415) 374 9579 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Bayworks Plumbing INC | Boris Elifael Agustin Gonzalez | info@bayworksplumbing.com | (415) 571 3050 | Other | Richmond · Contra Costa County | — | — |
| Bbig Construction Corp | Ghenadie Andruh | — | (650) 199 9647 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Bbp Pavers | Rafael Silva Santan Pires | — | (925) 497 3321 | Other | Concord · Contra Costa County | — | — |
| Bc Energy Services INC | Blake Andrew Cammack | — | (303) 808 1776 | Electricians | Concord · Contra Costa County | — | — |
| Bc Tile | Bc Tile | — | (415) 297 5092 | Other | El Cerrito · Contra Costa County | — | — |